Amyloid precursor protein fragment and acetylcholinesterase increase with cell confluence and differentiation in a neuronal cell line

This study addresses the developmental regulation of amyloid precursor protein (APP) fragments comprising the amyloid-β peptide (Aβ) and the amyloid-p promoting factor acetyicholinesterase (ACHE) in a mouse neuronal cell line (Neuro-2a). Results indicated that a 35-kDa amyloidogenic fragment of APP and the major molecular forms of AChE (G~1 and G~4) in Neuro-2a cells significantly increase with increasing levels of cell confluence. The foregoing molecules undergo further increases when neuroblastoma cells differentiate in the presence of dibutyryl cAMP. In contrast, a 17-kDa fragment of APP and butyrylcholinesterase were not affected by cell confluence or differentiation. These findings are the first to indicate that a selective Aβ-containing fragment of APP is subject to develop mental regulation. Moreover, our data show that the 35-kDa fragment and AChE forms respond in parallel to the same developmental stimuli, i.e., cell confluence and differentiation. This points to the existence of a functional relationship between both molecules, a notion that is consistent with the potential role that has been ascribed to AChE in both APP processing and the formation of amyloid deposits in Alzheimer's brains.